As a method for purifying chlorine, which comprises separating nitrogen and/or oxygen from crude chlorine containing nitrogen and/or oxygen, a method for separating a liquid or gas containing chlorine as a major component and a gas containing nitrogen and/or oxygen as major components by compressing and/or cooling, is illustrated, but there are problems that not only the compressing and/or cooling requires great energy, but also the installation cost is large and separation efficiency is bad.
Further, as a method for producing 1,2-dichloroethane by reacting chlorine with ethylene, for example, a method of reacting chlorine with ethylene by supplying simultaneously chlorine purified by the above-mentioned method and ethylene into 1,2-dichloroethane, is known.